🗳️ Solana Voting Program Listener & Indexer

This Rust project demonstrates how to build a real-time on-chain listener for a Solana program, decode Anchor-based accounts, and index the data into a PostgreSQL database using Diesel ORM. It also includes a simple CLI tool to query the indexed data.

⚠️ This is a learning-focused project meant to teach you the basics of indexing, decoding, WebSockets, SQL integration, and command-line tooling in Rust + Solana. It is not production-ready, but can be extended.

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✨ What You’ll Learn

✅ How to subscribe to Solana account updates using WebSockets
✅ How to decode on-chain data using Anchor discriminators
✅ How to write decoded data to PostgreSQL using Diesel ORM
✅ How to build a simple CLI to query your indexed blockchain state
✅ How to use tokio, spawn_blocking, and async Rust patterns

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🧠 How It Works

• Connects to the Solana Devnet via program_subscribe (WebSockets)
• Filters and decodes specific on-chain accounts (e.g. Poll)
• Persists data to a SQL database in real time
• Lets you query stored data using a CLI (built with clap)

You can easily replace the Poll model with your own program’s state.

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🛠️ Project Setup

1. Clone the Project

git clone https://github.com/your-username/voting-dapp-listener.git
cd voting-dapp-listener

2. Configure Your Program Edit src/main.rs:

let program_id = pubkey!("HH6z4hgoYg2ZsSkceAUxPZUJdWt8hLqUm1SoEmWqYhPh");

Replace this with your own deployed program’s ID. You can also update the struct in src/state/pool.rs to match your on-chain data.

3. Set Up PostgreSQL Install Postgres:

brew install postgresql@14
brew services start postgresql

Create user and database:

CREATE USER voting_user WITH PASSWORD 'test123!';
CREATE DATABASE voting_dapp OWNER voting_user;

4. Configure .env

Create a file called .env:

DATABASE_URL=postgres://voting_user:test123!@localhost/voting_dapp

5. Set Up Diesel

Install Diesel CLI:

cargo install diesel_cli --no-default-features --features postgres
Run the migrations:

diesel setup --migration-dir db/migrations
diesel migration run --migration-dir db/migrations
diesel print-schema --output-file src/db/schema.rs

🚀 Run the Listener

cargo run --bin voting-dapp-listener

Example output:

Listening for state changes to program: HH6z4hgo...

New Poll account updated:
ID: 12
Owner: F7x...
Name: Do you like Rust?
Description: Absolutely.
Start: 1716220000
End: 1716223600
Candidates: 3
Winner: 11111111111111111111111111111111

🔍 Querying with the CLI

In a new terminal window:

cargo run --bin cli -- list-polls

Example output:

🗳️ Poll #21: Final Vote | 1747695600000 → 1747785600000

🧠 Notes

Uses spawn_blocking to safely insert data from async context

WebSocket shutdown is cleanly handled with ctrl_c()

poll_id is used as the unique key for upserts

You can extend the logic for Candidates or Votes

🚧 Optional Extensions

Add filters to CLI (e.g. --owner, --active)

Add REST API layer over the SQL database

Index additional account types (candidates, votes)

📜 License

MIT